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the sea, a long line of surf tumbled incessantly over a continuous reef of coral.
I picked up one very fine specimen, which, though it weighed nearly a hundredweight, I resolved on getting transported to Edinburgh, and which now lies on the floor before me. It is a transverse cut of a portion of a large tree, including the pith, and measures twenty-three inches across. In the sections of trees figured by Mr. Witham in his interesting and valuable work, the original structure seems much disorganized : a granular radiating spar occupies the greater portion of the interior; and the tissue is found to exist in but detached portions. Here, on the contrary, the tissue exists unbroken from the pith to the outer ring. We may see one annual circle succeeding another in the average proportion of about ten per inch ; and though we cannot reckon them continuously, for there are darker shades in which they disappear,--shades which the polisher of the marble-cutter may yet succeed in dissipating the number of the whole must rather exceed than fall short of a hundred. However obscure the geologist may be in his eras generally, here at least is the record of one century. But how were its years filled? I sat beside the root of a newly-felled fir some six or eight seasons ago, and amused myself, when the severed vessels were throwing up their turpentine in minute transparent globules, in reckoning the years by the rings, from the bark inward. Here, I said, is the year in which the Reform Bill passed ; and this the year in which Canning died; and this the year of the great commercial crisis ; and this the year of Waterloo ; and this of the burning of Moscow. The yearly rings of the Oolite have no such indices of recollection attached to them : we see their record in the marble, but know no more of contemporary history than that, when forests showed their fringes of lighter green on the hill-sides, and cell and fibre swelled under the rind, the promptings of instinct were busy all around and beneath,—that the pearly ammonite raised its tiny sails to the breeze, as the belemnite, with its many arms, shot past below,—that nameless birds mingled with flying reptiles, -and that, while the fierce crocodile watched in his pool for prey, the gigantic iguanodon stretched his long length of eighty feet in the sand. But who shall reveal the higher history of the time? The reign of war and of death had commenced long before ; and who shall assert that moral evil had not long before cast its blighting shadows over the universe,—that there had not been that war in heaven in which the uncreated angel had overthrown the dragon,-or that unhappy intelligences did not wander, seeking rest, but finding none,' in an earth of waste places,' whose future sovereign still lay hid in the deep purposes of Eternity?
ASTREA OF THE OOLITE, SUTHERLAND.
The same deposit in which I found the wood embedded contains large masses of coral, all apparently of one species,
-not a branching coral, but of the kind which consists of large stone-like masses covered on the surface with stellular impressions, framed in polygons, and which composes the genus Astrea. I picked up one very fine specimen, which I have since got cut through and polished. It presents a polygonal partitioning, of a delicate cream-colour, that somewhat resembles the cells of a honeycomb. Each cell is filled with a brownish ground of carbonate of lime; and on this ground of brown there is a cream-coloured star, composed of rays that proceed from the centre to the sides. One of these corals measured two feet and a half across in one direction, by two feet in another; and if it grew as slowly as some of its order in the present scene of things, its living existence must have stretched over a term of not less extent than that of its contemporary the pine of the hundred rings. Some of the masses seem as if still adhering to the rocks on which they originally grew; the pentagonal cells are still open, as if the inhabitants died but yesterday; and the star-like lines inside still retain their original character of thin partitions, radiating outwards and upwards from a depressed centre. In other instances they have been torn from their places, and lie upturned in the shale, amid broken shells and fragments of wood. I brought with me one curious specimen perforated by an ancient pholas : the cavity exactly resembles those cavities of the existing Lithodomus shell which fretted so many of the calcareous masses that lay scattered on the beach on every side; but it is shut firmly up by the indurated shale in which the specimen itself had lain buried, and a fragment of carbonized wood lies embedded in the en
The cave is curtained across by a wall of masonry immensely more ancient than that which converted into a prison the cave of the Seven Sleepers.
RECENT TYPES OF FOSSILS.
An imagination curious to re-erect and restore finds assistance of no uninteresting kind among the pools and beneath the bunches of sea-weed which we find scattered, at the fall of the tide, over the surface of the Navidale deposits. One very minute pool of sea-water, scarcely thrice the size of a common washing basin, and scarcely half a foot in depth, furnished me with recent types of well-nigh all the fossils that lay embedded for several feet around it; though there were few places in the bed where these lay more thickly. Three beautiful sea anemones,—two of crimson, and the third of a greenish-buff colour,--stretched out their sentient petals along the sides; and the minute currents around them showed that they were all employed in their proper trade of winnowing the water for its animalcular contents, working that they might live. One of the three had fixed its crimson base on the white surface of a fossil coral; the pentagonal cavities, out of each of which a creature of resembling form had once stretched its slim body and still minuter petals, to agitate the water with similar currents, were lying open around it. In another corner of the pool a sea-urchin was slowly dragging himself up the slope, with all his red fleshy hawsers that could be brought to bear, and all his nearer handspokes hard strained in the work. His progress resembled that of the famous Russian boulder, transported for so many miles to make a pedestal for the statue of Peter the Great; with this difference, however, that here it was the boulder itself that was plying the handspokes and tightening the ropes. And lo! from the plane over which he moved there projected the remains of creatures of similar type;—the rock was strewed with fossil handspokes, greater in bulk than his, and somewhat diverse in form, but whose general identity of character it was impossible to mistake. The spines of echini, fretted with lines of projections somewhat in the style of the pinnacles of a Gothic building, lie as thickly in this deposit as in any deposit of the Chalk itself. The pool had its zoophytes of the arborescent form,- the rock its flustra; the pool had its cluster of minute muscles,—the rock its scallops and ostrea; the pool had its buccinidæ,—the rock its numerous whorls of some nameless turreted shell; the pool had its cluster of serpulæ,—the serpulæ lay so thick in the rock, as to compose, in some layers, no inconsiderable proportion of its substance.
BRORA COAL-FIELD OTHER THAN THE TRUE COAL MEASURES.
A COAL-FIELD in other than the true Coal Measures is always an object of peculiar interest to the geologist; and
the coal-field of Brora is, in at least one respect, one of the most remarkable of these with which geologists are yet acquainted. The seams of the well-known Bovey coal of South Devon,-a lignite of the Tertiary,-are described as of greater depth; but it burns so imperfectly, and emits so offensive an odour, that, though used by some of the poorer cottagers in the neighbourhood, and some of the local potteries, it never became, nor can become, an article of commerce. It is curious merely as an immense accumulation of vegetable matter passing into the mineral state,-as, shall I venture to say, a sort of half-mineralized peat of the Tertiary,-a peat moss that, instead of overlying, underlies the diluvium. In the Brora coal, as might be inferred from its much greater age, the process of mineralization is more complete ; and it furnishes, if I mistake not, the only instance in which a coal newer than that of the carboniferous era has been wrought for centuries, and made an article of trade. There were pits opened at Brora as early as the year 1598: they were re-opened at various intermediate periods in the seventeenth and eighteenth centuries; on one occasion, in the middle part of the latter, by Williams, the author of a Natural History of the Mineral Kingdom, which has been characterized by Lyell as a work of great merit for its day;' and during twelve years of the present century, from 1814 to 1826, there were extracted from but a single pit in this field no fewer than seventy thousand tons of coal. The Oolitic coal-field of Sutherland stands out in prominent relief amid the ligneous deposits that derive their origin from the later geological floras. And yet its commercial history does not serve to show that the speculations of the miner may be safely pursued in connexion with any other than that one wonderful flora which has done so much more for man, with its coal and its iron, than all the gold mines of the world. The Brora workings were at no time more than barely remunerative; and the fact that they